High power Quasi-resonant SMPS for Audio Amplifiers, capable of delivering 3600W continuous and 4500W peak power. This Power supply can be used for high power Class AB amplifiers with 2 or 4 supply rails, such as the LME49810 based amplifiers, or class H, 2 tier amplifiers. Stock available output voltages are +-75V DC at 24A, and +-87V DC at 0.5A, or +-55V DC at 8A and +-110V at 12.5A. Other voltages are available on request. The topology used is soft-switched half-bridge resonant topology and the output voltage is within +-5% of the nominal voltage when the current draw is varying from 0-100% with constant mains input voltage. The main advantage is lower size, weight and cost compared with a similar closed loop regulated SMPS and better efficiency compared with the mains transformer and rectifier plus capacitors due to the fact that the transformer is driven with almost 50% duty cycle all the time, and the current through the switches has sinusoidal shape, and there are no output inductors. The SMPS features overcurrent protection which limit the output current at about 130% of the maximum peak power, about 4800W. The power supply can be used both at 110V mains voltage and 230V mains voltage, using voltage doubling when is used with 110V input.